/*global window, document, jQuery */

/*
* jQuery Form Example Plugin 1.5.2
* Populate form inputs with example text that disappears on focus.
*
* e.g.
*    $('input#name').example('Bob Smith');
*    $('input[@title]').example(function () {
*        return $(this).attr('title');
*    });
*    $('textarea#message').example('Type your message here', {
*        className: 'example_text'
*    });
*
* Copyright (c) Paul Mucur (http://mudge.name), 2007-2011.
* Dual-licensed under the BSD (BSD-LICENSE.txt) and GPL (GPL-LICENSE.txt)
* licenses.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.    See the
* GNU General Public License for more details.
*/
(function ($) {
    "use strict";

    $.fn.example = function (text, args) {

        var isCallback = $.isFunction(text),
            options = $.extend({}, args, { example: text });

        return this.each(function () {

            var o, clearExamples, $this = $(this);

            /* Merge the plugin defaults with the given options and, if present,
            * any metadata.
            */
            if ($.metadata) {
                o = $.extend({}, $.fn.example.defaults, $this.metadata(), options);
            } else {
                o = $.extend({}, $.fn.example.defaults, options);
            }

            clearExamples = function () {
                $(this).find('.' + o.className).val('');
            };

            /* The following event handlers only need to be bound once
            * per class name. In order to do this, an array of used
            * class names is stored and checked on each use of the plugin.
            * If the class name is in the array then this whole section
            * is skipped. If not, the events are bound and the class name
            * added to the array.
            */
            if (!$.fn.example.boundClassNames[o.className]) {

                /* Because Gecko-based browsers cache form values
                * but ignore all other attributes such as class, all example
                * values must be cleared on page unload to prevent them from
                * being saved.
                */
                $(window).bind('unload.example', function () {
                    $('.' + o.className).val('');
                });

                /* Clear fields that are still examples before any form is submitted
                * otherwise those examples will be sent along as well.
                *
                * Where possible, attempt to delegate this event handler so that
                * all forms are bound now and in the future.
                */
                if ($.fn.on) {
                    $('body').on('submit.example', 'form', clearExamples);
                } else if ($.fn.delegate) {
                    $('body').delegate('form', 'submit.example', clearExamples);
                } else if ($.fn.live) {
                    $('form').live('submit.example', clearExamples);
                } else {
                    $('form').bind('submit.example', clearExamples);
                }

                /* Add the class name to the array. */
                $.fn.example.boundClassNames[o.className] = true;
            }

            /* Several browsers will cache form values even if they are cleared
            * on unload, so this will clear any value that matches the example
            * text and hasn't been specified in the value attribute.
            *
            * If a callback is used, it is not possible or safe to predict
            * what the example text is going to be so all non-default values
            * are cleared. This means that caching is effectively disabled for
            * that field.
            *
            * Many thanks to Klaus Hartl for helping resolve this issue.
            */
            if ($this.val() !== this.defaultValue && (isCallback || $this.val() === o.example)) {
                $this.val(this.defaultValue);
            }

            /* Initially place the example text in the field if it is empty
            * and doesn't have focus yet.
            */
            if ($this.val() === '' && !$this.is(':focus')) {

                /* The text argument can now be a function; if this is the case,
                * call it, passing the current element as `this`.
                */
                $this.addClass(o.className).val(isCallback ? o.example.call(this) : o.example);
            }

            /* Make the example text disappear when someone focuses.
            *
            * To determine whether the value of the field is an example or not,
            * check for the example class name only; comparing the actual value
            * seems wasteful and can stop people from using example values as real
            * input.
            */
            $this.bind('focus.example', function () {

                if ($(this).is('.' + o.className)) {
                    $(this).val('').removeClass(o.className);
                }

            }).bind('change.example', function () {

                if ($(this).is('.' + o.className)) {
                    $(this).removeClass(o.className);
                }

            }).bind('blur.example', function () {

                if ($(this).val() === '') {

                    /* Re-evaluate the callback function every time the user
                    * blurs the field without entering anything. While this
                    * is not as efficient as caching the value, it allows for
                    * more dynamic applications of the plugin.
                    */
                    $(this).addClass(o.className).val(isCallback ? o.example.call(this) : o.example);
                }

            });
        });
    };

    /* Users can override the defaults for the plugin like so:
    *
    *     $.fn.example.defaults.className = 'not_example';
    */
    $.fn.example.defaults = {
        className: 'example'
    };

    /* All the class names used are stored as keys in the following array. */
    $.fn.example.boundClassNames = [];

} (jQuery));